node-eventstore-postgre

Why I create this eventstore?

I firstly checked Greg Young's event store, but it only provide atom REST interface for node.js, which need too many round trips (each event for each round trip) to get events from a given aggregate.

Later I tried to find node.js event store implementations, however, many are using NOSQL databases which I don't think it will support transaction very well.

Finally, I decide write a simple one using rational database.

Inspired by Greg Young's cqrs document.

Install

npm install node-eventstore-postgre

APIs

I am using coffeescript to the usages. before everything, do this

EventStore = require 'node-eventstore-postgre'
eventStore = new EventStore 'postgres://ronliu:123456@localhost/test', publish   #Pass in postgre connection string and publish method
eventStore.init()   #Initialise necessary tables and functions using create if not exists style

Get events from a given aggregate id

It will take 2 arguments:

• aggregateId
• startOverVersion, like given 3, it should return events from version 4

events = eventStore.readEvents aggregateId, statOverVersion

Given aggregate id, output a snap shot with version

It will take 2 arguments:

• aggregateId

snapshot = eventStore.readSnapshot aggregateId # {data: aggregate, version: version} or undefined

Write events to

It will take 4 arguments:

• aggregateId
• aggregate type
• originating version: the version when we read used to check optimistic concurrency conflicts
• events array
• snapshot

eventStore.writeEvents aggregateId, 'customer', 2, [
	{eventName: 'customerAdded', data: name: 'ron', createdOn: new Date()},
	{eventName: 'customerActivated', data: comment: 'good customer'},
], name: 'john', isActive: true

Status

• From 0.2, it support snapshot